This invention relates to personal alarm systems and in particular to portable, self-locating, voice-activated personal alarms.
Personal alarms are known. They detect the presence of a specific danger and provide a signal for giving an alarm and for summoning help. It is also known to transmit the danger detection signal via a radio transmitter to a common base station which supervises multiple personal alarms. It is also known to use a wireless telephone communications system for that purpose. The incorporated references disclose a class of portable, self-locating personal alarms which include a satellite global positioning receiver for providing an accurate location of the monitor. These disclosed devices do not disclose a voice-activated device. It is desirable to provide such capability.
The need is met by the present invention which incorporates a satellite global positioning receiver, a specific danger sensor, a voice activation circuit, and a radio transmitter. In a specific embodiment, the satellite global receiver relies upon the U.S. Global Positioning System (xe2x80x9cGPSxe2x80x9d). In another specific embodiment, the radio transmitter is provided by a wireless telephone using an existing wireless communications network and therefore also provides a two-way voice communication channel. In a specific embodiment of the invention, a distress phrase such as xe2x80x9cHELP!xe2x80x9d spoken into a microphone is recognized and activates the radio transmitter to transmit the current global location. The detection of a specific danger by the danger sensor also activates the transmission of the current global location.